Federal Aviation Administration Revised Rate of Heat Release Test Method 2013 December Triennial Conference Philadelphia, PA USA Michael Burns, FAA Tech Center

Agenda Test Method Background for Revision Improvements Prototype Data Next

Heat Release Rate Test Method Required by Federal Aviation Administration Qualify large surface area interior materials for use in commercial passenger aircraft o Ceilings o Stow bins o Sidewalls Federal Register 14 CFR parts 25 and 121 o Description o Use o Calibration o Pass / Fail criteria

Revised Heat Release Rate Test Method Goal: Simplify and Streamline the Test Method Multi-laboratory studies in which the same material was tested at different locations indicate reproducibility of test results can be improved. Many factors can contribute to poor agreement between test laboratories. This presentation describes a detailed revision of the test apparatus conducted by the International Aircraft Materials Fire Test Working Group to better standardize components, procedures and calibration of equipment for this test method.

Categories Of Improvements Airflow (Dual Flow to Single Flow) Standardized Construction Procedures / Software Calibration Equipment Changes in Documentation (Chapter HR)

Airflow – Single Flow Design OSU: Orifice Meter, Natural 3:1 Airflow Split HR2: Mass Flow Meter Controlled

Removal of Bypass Air and Components Chimney Baffle Plate Outer Pyramid Bypass Air Manifold Piping Surplus Gasket Material and Hardware Orifice Meter/Mercury Manometer

Removal of Bypass Air and Components PROS Single air source o 1 MFM Req’d o Smaller Compressed Air System Req’d Easier to clean, inspect, maintain Fewer Components Lower Manufacturing / Operating costs Quieter system Thermocouples operating in a better performance range Higher gain in the Thermopile output signal Lower Calibration Factor (Approx. 4.0 kW/m 2 /mV or 0.09 kW/mv) CONS Higher Exhaust Gas Temperatures (approx. 500 degrees F)

Airflow Defined Air Quality -“…free of oil mist, water and foreign particles” Airflow (MFM/MFC Controlled) -Calibrated To STP 0º C at 760 mmHg -Accuracy: 1% Reading, 0.2% Full Scale -Flow Rate: 20 ± 0.5 SCFM -Positioned within 24 inches of the inlet port to the system -Provision for Flow Straightening Piping

¼ inch AluminumUnchangedHolding Chamber Door UnchangedAir Distribution Plate / Alum.Not SpecifiedExhaust Stack Covering (New) ± 0.005Not Specified1/8 inch Retaining Rod ± 0.004(0.049 ± 0.002)Main Body Not SpecifiedGlobar Pan Not SpecifiedHolding Chamber Not SpecifiedSecond Stage Plate Not SpecifiedLower Air Plenum Insulation - Thermal Conductivity Criteria Overlap Criteria Component Metal Thickness & Tolerances Table Standardized Construction New Previous Component

0.042 ± 0.004(0.042 ± 0.002)Diamond Mask ± 0.003(0.030 ± 0.008)Reflector Plate 24-Gauge StealSample Holder Plate ± 0.003(0.031 ± 0.002)Outer Pyramid (Removed) Not SpecifiedRadiation Doors (2) ± 0.002UnchangedInner Pyramid (Modified) UnchangedChimney (Removed) UnchangedBaffle Plate (Removed) UnchangedSample Holders UnchangedHolder Spring UnchangedRetaining Ring Standardized Construction New Previous Component

HR2 Exhaust Assembly 1” Stiffening Doubler 1” Flange

Standardized Construction  Exhaust Stack Mounting o #10-32 x ¾” Bolts / Washers / nuts (28) o Gasket o / Aluminum Covering o No substitutions permitted  Main body o Dimensions o Observation window o Inner radiation doors o Rear globar pan o Reflector plate o Diamond plate shaft o Upper Pilot/Calibration Burner o Second Stage Plate  Hole pattern (Centered in Chamber)  Perimeter sealed  Removable

Standardized Construction  Holding Chamber o Dimensions o Outer door o Preheat sample position  Specimen Holder / Components o Dimensions o Retaining Ring o Spring Plate o Retaining Rod o Drip Pan  HFG Mounting o Refractory Board (Thickness, HFG flush mount) o Corner HFG position

Standardized Thermopile / Globars Thermopile mV Generating System o New Thermocouples (9) o Detailed Wiring Diagram o 96 inch Overall Length o 24 Gauge, Solid Conductor, Thermocouple Grade Wire o Quick Disconnects o Cold Junctions Centrally Located in Lower Plenum: 1.5 inch Spacing o Reference Junction: Closest To Air Inlet Globars o Construction: CHZ, Length, Diameter, Resistance o Rheostat control of upper/lower pairs or individually o Advisory on final power adjustments / Uniformity o Voltage Fluctuation Tolerance (Globars)

New Procedures: Calibration Goals: Achieve better stability at each step change in flow Obtain largest mV rise possible for each step change in flow (resulting in the low calibration factor) Linear analysis to mV rise per step change in flow Low % error (<5%) Reduce time req’d to complete the calibration process Reduced use of Methane Gas Make it easier

New Procedures: Calibration Replaced Wet Test Meter with Mass Flow Meter (MFM) Calibration Gas MFM o Thermal-based o 0.25 inch inlet/outlet fittings o Calibrated annually with NIST traceability o Calibrated for Methane gas o Accuracy: 0.5% Reading, 0.1% Full Scale, 2-sigma level of confidence o STP 0ºC at 760 mmHg o Signal Output To Data Acquisition System o Flow deviation of < 0.2 SLPM Dual Purpose Burner (Upper) o Calibration Burner (Removed T-Burner) o Upper Pilot Burner during testing – 2 SLPM / Air (Approx. 50/50 Ratio)

New Procedures: Calibration Calibration Method Changes o Optimized flow settings from 1,4,6,8 L/min to 1,2,3,4 SLPM o Entire calibration sequence defined (Beginning to end) o 3 minute Preheat at 4 L/min o Step Change: 1-2, 1-3, 1-4 SLPM o Longer dwell – Increased from 2 to 3 minutes (last 10 second average) o Methane MFM/MFC output recorded with Thermopile output o Only 3 step changes in flow (previously 5) o Exhaust ventilation system must be on Calibration Pass / Fail Criteria o 5% STDEV error between the three calibration constants derived during the calibration process (1-2, 1-3, 1-4 SLPM)

HR2 Prototype CALIBRATION PARAMETERS METHANE FLOW (SLPM) THERMOPILE OUTPUT (mV) Low RangeTARGETHigh RangeLow RangeTARGETHigh Range CALIBRATION FACTOR RANGE Low RangeTARGETHigh Range 0.07 kW/mv 0.08 kW/mV 0.09 kW/mV 3.0 kW/m 2 /mV 3.5 kW/m 2 /mV 4.0 kW/m 2 /mV

New Procedures: Heat Flux HFG Type: Replaced Gardon with Schmidt- Boelter HFG Guidance: Paint / Care / Mounting New insitu method (Center) o / New Uniformity Tolerance (4-Corners) o /- 0.10

Calibration Factor / HRR Equation DeletedSample Area Moved to HRR Calculation

HR2: Total Heat Release Calculation

Chapter HF: Definitions Calibration Factor (K h ) - Correlates the heat released by a specimen when burned to the known heat content of Methane. Thermopile Mass Flow Meter (MFM)/Mass Flow Controller (MFC) Methane Gas (CH4) - Minimum purity of 99% Supply pressures – 20 ± 2 psig, 30 ± 2 psig NIST - The National Institute of Standards and Technology (USA) NIST Traceability - A calibration entity using NIST traceable calibration instrumentation. o Heat flux gauges (Chapter HF) o Data acquisition / Display devices o Flow meters (System Airflow and MFM for thermopile calibration) Stability Criteria - Heat flux, Chamber equilibrium

Chapter HF: Calibration Requirements and Frequency Equipment o Heat Flux gauges o Data Acquisition System/Display Devices o MFM / MFC (Air) o MFM / MFC (Methane) Procedures o System Heat Flux o Heat Flux Uniformity o Thermopile (Gas Calibration)

Chapter HF: Misc. General / Scope Drawings o System Overview Drawing (assembled) o Individual Components - 29 Detailed Drawings Test Procedure o Aluminum foil thickness criteria o Sample Insertion / Removal Time - Approximately 3 to 5 seconds o Cleaning procedures Requirements o 65/65 (Peak HRR / Total HR) - Unchanged o < 80 % must pass

HR2 Prototype Testing Materials (5 coupons each) 1.Schneller Panel (2012 RR) 2.Light Brown Panel (2012 RR)

HR2: 53.5

HR2: 69.6

HR2: 47.9

HR2: 36.9

Next Participation in 2013 Round Robin Conformance Documentation Development Additional Unit Buildups for Comparative Testing